I've been messing around with the fetch() api recently, and noticed something which was a bit quirky.

let url = http://jsonplaceholder.typicode.com/posts/6;



let iterator = fetch(url);



iterator

  .then(response => {

      return {

          data: response.json(),

          status: response.status

      }

  })

  .then(post => document.write(post.data));

;

post.data returns a Promise object.
http://jsbin.com/wofulo/2/edit?js,output

However if it is written as:

let url = http://jsonplaceholder.typicode.com/posts/6;



let iterator = fetch(url);



iterator

  .then(response => response.json())

  .then(post => document.write(post.title));

;

post here is a standard Object which you can access the title attribute.
http://jsbin.com/wofulo/edit?js,output

So my question is: why does response.json return a promise in an object literal, but return the value if just returned?